N-para secondary hydrocarbon amino phenylmorpholines

ABSTRACT

N(P-SEC. AMINOPHENYL) MORPHOLINE AND PIPERAZINE AND 2,6-DIMETHYL MORPHOLINE COMPOUNDS ARE DISCLOSED WHICH ARE RUBBER ANTIOZONANTS.

N-PARA SECONDARY HYDROCARBON AMINO PHENYLMORPHOLINES Richard W. .Kibler, Cuyahoga Falls, Ohio, assignor to The Firestone Tire & Rubber Company, Akron, Ohio No Drawing. Original application July 21, 1965, Ser. No.

473,821. Divided and this application Mar. 17, 1969,

Ser. No. 829,826

Int. Cl. C07d 87/40 US. Cl. 260-247 8 Claims ABSTRACT OF THE DISCLOSURE N(p-sec. aminophenyl) morpholine and piperazine and 2,6-dimethyl morpholine compounds are disclosed which are-rubber antiozonants.

This application is a division of Kibler Ser. No. 473,821 filed July 21, 1965. I I This invention relates to new antiozonants and antioxidants (referred to herein as antiozonants) for use in natural and synthetic rubber vulcanizates, their preparation, rubbers containing them, and the method of curing rubbers in the presence of the new compounds.

The new compounds have the following formula CHI-CH2 in'which (a) When X is O, R is hydrogen or an alkyl group of 1 to carbon atoms, and R and R are a straight or branched chain or hydroxy alkyl group of 1 to carbon atoms or an aryl group of the class consisting of phenyl and naphthyl and lower alkyl and alkoxy derivatives of said aryl group in which the alkyl group is a lower branched or straight chain alkyl group of 1 to 4 carbon atoms); and R CHR may be a cycloalkyl group of 5 to 8 carbon atoms; and

(b) When X is NH or R is hydrogen, and R and R is each hydrogen or one may be hydrogen and the other a straight or branched chain alkyl group of 1 to 10 carbon atoms or an aryl group (e.g. phenyl, naphthyl, alkylphenyl, alkoxyphenyl, etc., in which the alkyl group is a lower straight or branched chain group of 1 to 4 carbon atoms), and R CHR may be a cycloalkyl group of 5 to 8 carbon atoms;

Repre'sentativecompounds are:

N-(p-isopropylaminophenyl) morpholine N-(p-sec-butylaminophenyl) morpholine N-(p-sec-hexylaminophenyl) morpholine N-(p-2-octylaminophenyl) morpholine N-(p-cyclohexylaminophenyl) morpholine N (p-isopropylaminophenyl -2,6-dimethyl morpholine. N-(p-cyclohexylaminophenyl)-2,6-dimethyl morpholine N- [p-2- 3-phenylpropyl) aminophenyl] morpholine N-[p-2-(1,3-diphenylpropyl)aminophenyl] morpholine N- [p-2- 3-p-tolylpropyl) aminophenyl] morpholine N-[p-2-(3-p-ethoxyphenylpropy1)aminophenyl] morpholine N-(p-isopropylarninophenyl) piperazine N-.(p-cyclohexylaminophenyl) piperazine N,N'-bis(p-isopropylaminophenyl) piperazine United States Patent 0 ice N- [p-2- (4-hydroxy-4-methylpentyl aminophenyl] morpholine N- [p 2- (4-hydroxy-4-methylpen-tyl aminophenyl] -2,6-

dimethyl morpholine N- p-2- 5 -hydroxyhexyl) amino phenyl] -2,6-dimethyl morpholine In each of the compounds of the foregoing list in which the amine group is substituted by a secondary alkyl group, the substituent on the alpha carbon is methyl.

The rubbers which may be improved by the antiozonants are diene rubbers, i.e. natural and synthetic homopolymers and synthetic copolymers of hydrocarbon dienes containing 4 and 5 carbon atoms (viz. butadiene, isoprene and piperylene), the copolymers being copolymers of such dienes with monomers such as styrene, alkyl-substituted styrenes, vinyl toluene, acrylonitrile, lower-alkyl acrylate and methacrylate esters, etc.

The antiozonants are readily prepared from N(4-nitrophenyl) morpholine, or an identically substituted 2,6- disubstituted morpholine (the substituents being alkyl groups of 1 to 8 carbon atoms), or N(4-nitrophenyl) piperazine or N,N'-bis-(4-nitrophenyl) piperazine. The nitro compound is reacted with a ketone and hydrogen which on reduction reaction with the nitro group (usually with a catalyst) gives the desired aminophenyl grouping. The ketone has the formula O:CR R in which R, and R have the values given in the foregoing formula for the antiozonant. These ketones include:

acetone cyclohexanone 2-octanone 2-butanone 4-methyl-2-butanone propiophenone benzophenone dibenzylketone phenylacetone acetophenone cyclohexyl phenyl ketone and ketones in which there are homologous alkyl groups of 1 to 10 carbon atoms.

The following examples illustrate the preparation of such compounds, and the preparation of N(4-nitrophenyl) morpholine and N(4-nitrophenyl) 2,6-dimethyl morpholine is included.

PREPARATION OF N-(4-NITROPHENYL) MORPHOLINE In a 1-liter round-bottom flask fitted with a reflux condenser, a thermometer and a mechanical stirrer was placed 158 gr. (1 mole) of l-chloro-4-nitr0benzene and 264 ml. (ca. 3 moles) of morpholine. The reactants were heated at reflux with stirring for about 4 hours and then allowed to cool. The reaction mixture was slurried with water and filtered. The yellow crystalline solid was washed with water and air dried. The product melted at 150- 151 C.

EXAMPLE 1 Preparation of N-(p-isopropylaminophenyl) morpholine The N-(4-nitrophenyl) morpholine (10.4 gr., 0.05

mole), acetone (6.4 gr., 0.11 mole), glacial acetic acid (1 3 Analysis.-Calcd for C H N O (percent): C, 70.88; H, 9.15; N, 12.72. Found (percent): C, 71.00; H, 9.25; N, 12.63.

4 Paar hydrogenator apparatus at an initial hydrogen pressure of 50 p.s.i.g. When the uptake of hydrogen had ceased, the reaction mixture was filtered to remove the catalyst EXAMPLE 2 and evaporated leaving an oily residue which was purified Preparation of N-(p-Z-octylaminophenyl) morpholine 5 s g g z g on alumma' The product was a red The title compound was prepared in the same manner Analysis,- Calcd for C H N O (percent): C, 72.53; as in Example 1 except that 2-octanone was used in place H, 9 74; N, 11.28, Found (percent): C, 71.40; H, 9.71; of the acetone. The product was a colorless solid melting N, 1097, at 6061 C. 10 EXAMPLE 7 Analysis.Calcd for C H N O (percent): C, 74.74; H, 10.20; N, 9.40. Found (percent), 0, 74.45; H, 10.42; Prepamflon of N-(p-cyclohexylamlmphenyl)- N, 9.65. 2,6-d1methyl morphohne XAM 3 This compound was prepared in the same manner as in i I" Example 6 except cyclohexanone was used in place of Preparation of N (p cyc1oheXy1am mOpheny1) morphol He 10 the acetone. The oil product was purified by chromatog- This compound was prepared 1n the same manner as raphy on alumina. shown in Example 1 except that cyclohexanone was used Analysis calcid for CIBHzsNZO (percent): C, 7435; in place of acetone. The product was worked up and puri- H 9.78; N Found (percent): C 74.92; fied in the usual manner and melted at 126-127 C. 20 N, 951.

Analysis.Calcd for C H N O (percent): C, 73- EXAMPLE 8 H, 9.29; N, 10.76. Found (percent): C, 73.65; H, 9.39; N, 11 O7 Preparation of N-(p-cyclohexylammophenyl) 4 plperazlne A mixture of N-(p-nitrophenyl) iperazine (10.3 gr., Preparauon of N (P sec butylamfnophenyl) molphohne 25 0.05 mole), cyclohexanone (5.4 gr., 0.055 mole) glacial T Compound was Prepared the Same manner 'f acetic acid (1 ml.), platinum oxide (0.1 gr.) and absolute Sh in EXamP1e 1 except that z'butanone w used ethanol (100 ml.) was hydrogenated at an initial hydrogen place of the acetone. The colorless crystalhne product pressure of 50 psig' After the uptake of hydrogen had me at 30 ceased, the reaction mixture was filtered and evaporated. Analysis-4316C for CMHZZNZO (Percent): 71:76; The residue was dissolved in ether (only partially soluble) H, 9.46; 1 Found (P 71-70; 9'36; and filtered. The ether soluble material was chromatographed on alumina. The ether eluates upon recrystalliza- EXAMPLE 5 tion from ether melted at 101102 C. Preparation of N-[p-2-(4-methylpentyl)aminopheny p igg zggi gs iQ, 1 5.lf (percent). N 16.20- morphohne The antiozonants are added to the rubber in any usual This compound was prepared in the same manner as antiozonant amount together with sulfur and other comshown in Example 1 except that 4-methyl-2-pentanone pounding ingredients and cured at a usual temperature. was used in lace of the acetone. The product was isolated in the u ual manner and melted at 6466 C. MORPHOLINE ANTIOZONANT CURES y for 15 26 2 (Percent): 7323? The following table gives the physical properties of test H, 9.99; N, 10.68- (F c, 715-05; 10-10; samples containing 2 parts of diflerent antiozonants in butadiene-styrene copolymer (GR-S) in a usual sulfuritro h n 1 26 dimeth 1 containing formula, the rubbers having been cured for Preparatmn of gg g g y y minutes and 280 F., and then subjected to aging 2 days in an oven at 212 F., and antiozonant evaluation In a l-liter round-bottom flask fitted w1th a reflux conin a dynamic test on Samples exposed to an atmosphere denser, a mechanical stlrrer and athermometer was placed Containing 60 parts per million of ozone for 7 hours at 158 gr. (1.0 mole) of 1 -chloro-4-nitrobe nzene and 351.0 r The ozone cracking Was graded on this Scale: gr. (3.0 moles) of 2,6-d1methylmorphol1ne. The react1on 00 very, very Slight 8L) and Slight (SL), with a plus miXtl-lfe Was heated at reflux Wlth Surfing for four hours or minus to indicate greater or less cracking, respectively, 9 0 and filtered- The Orange crystanme Product was than indicated by the abbreviation. The test materials are a l identified as EXAMPLE 6 A N( D l h 1) h 1 a p-1sopropyam1nop eny morp o1ne Preparation f henyl) B=N(p-sec-butylaminophenyl) morpholine lmet y morp 0 me C=N(p-2-octylaminophenyl) morpholine The N-(p-nitrophenyl)-2,6-dimethyl morpholine (11.8 D=N(p-cyclohexylaminophenyl) morpholine gr., 0.05 mole), acetone (3.2 gr., 0.055 mole), glacial E=N(p-isopropylaminophenyl)-2,6-dimethyl morpholine acetic acid (1 ml.), platinum oxide (0.2 gr.), and absolute 60 F=N(p-cyclohexylamiuophenyl)-2,6-dimethyl morphoethanol ml.) were mixed and hydrogenated on a line Test material A B C D E F Physical properties:

Before aging:

300% modulus, p.s.i 1,475 1,475 1,500 1,325 1,500 1,500 400% modulus, p.s.i 2,200 2,200 2,400 2,100 2,275 2, 300 Tensile strength, p.s.i 3,350 a, 200 3,700 3,400 3, 300 3,375 Elongation, percent 580 620 580 550 560 560 After aging:

300% modulus, p.s.i 2, 500 2,525 2,700 2, 300 2,000 2,400 Tensile strength, p.s.l 2,800 2,525 3,225 2,775 2, 900 2, 825 Elongation, percent 300 300 320 Ozone cracking v.v.sl.+

Toxicity tests on all of these compounds showed them to be devoid of any adverse toxic eflect.

What I claim is:

1. A compound of claim 8 which is N- (p-2-octyl-aminophenyl) morpholine.

2. A compound of claim 8 which is N-(p-isopropylaminophenyl)-2,6-dimethyl morpholine.

3. A compound of the formula and wherein R is cycloalkyl of 5 to 8 carbon atoms or secondary alkyl of 3 to 10 carbon atoms in which a substituent on the alpha carbon is methyl.

4. 4-[p-(isopropylamino)phenyl]morpholine of the for- 15 mula /GH; 0 N-Q-NH 0% 5. 4-[p-(l-methylpropylamino)phenyl]morpholine of the formula C o NNH 0Q L/ 6. 4- [p- 1,3-dimethylbutylamino)phenyl1morpho1ine of the formula CH GH(CHu)2 7. 4-[p-(cyclohexylamino)phenyl]morpholine of the formula 8. A compound having the formula U.S. Cl. X.R. 

